1. Field of the Invention
This invention relates to a clamping apparatus and more particularly to a clamping apparatus having a force multiplying linkage capable of applying to a workpiece a force which is substantially greater than the actuating force applied to the clamping apparatus.
2. Description of the Prior Art
Conventional clamping devices as illustrated and described in U.S. Pat. Nos. 438,104; 1,947,607; 2,386,567 and 2,835,291 provide a lever or movable power arm for applying and releasing a clamping force through a series of linkages to engage a workpiece between a pair of coacting jaws. Once the actuating force has been applied and the coacting jaws urged into clamping relationship with the workpiece, the actuating force is removed from the lever or power arm. A suitable locking means maintains the jaws in clamping relationship with the workpiece.
In instances where a large force is required to be applied to a workpiece by the coacting jaws, the limited actuating force is insufficient to apply the resultant clamping force without providing additional adjusting apparatus and locking means to the clamping device. Furthermore, in instances of limited work area it is not feasible to utilize a large and cumbersome clamping device to generate a corresponding large clamping force. Problems are also encountered in the application and release of the clamping force to provide for efficient operation of the clamping device. Furthermore, many operations which require the securing of a workpiece do not permit extensive adjustments to be made to the clamping device before the clamping force is generated and subsequently released. However, conventional clamping devices require such adjustments to be made.
There is need to provide apparatus for clamping a workpiece that is capable of generating a clamping force which is substantially greater than the actuating force without requiring extensive adjustments to be made to the clamping device once the actuating force has been applied. The clamping device must be lightweight with as few moving parts as necessary to insure the quick application and release of the clamping force to the workpiece.